1. Field of the Invention
This invention relates to a semiconductor device having an integrated circuit including a transistor and a manufacturing method thereof. In specific, this invention relates to a sheet which has an integrated circuit including a transistor as a control circuit and has a heat generating function.
Note that the term “semiconductor device” in this specification refers to a device in general that can operate by utilizing semiconductor characteristics, and an electro-optical device, a semiconductor circuit, and an electronic device are all included in the semiconductor device.
2. Description of the Related Art
Disposable hand warmers have so far been generally used for warmth by being put on a chest, in a pocket, or the like. In recent years, hand warmers that are filled with a gel moisturizing agents and heated by a microwave oven when they are used have been used.
The temperature of such hand warmers cannot be controlled and there is a possibility of causing low temperature burns when the hand warmers are in contact with human skin for a long time. In specific, in the case of warming a person who is physically challenged due to injury, decrepitude, or the like, the hand warmer may be kept in contact with the physically challenged person due to inattention of a care taker and may cause a low temperature burn on the physically challenged person. In addition, in the case of warming a newborn baby or an infant whose thermoregulatory function is insufficient, the hand warmer is avoided because there is also a possibility of causing low temperature burns.
In order to warm a newborn baby or an infant, there is a heating apparatus called a heating pad for warming hands and feet. However, like the hand warmer, there is also a possibility of causing low temperature burns when the heating pad is kept in contact with human skin for a long time. In addition, since heating apparatuses which are in contact with human skin obtain electric power from an outlet through a wiring code, the heating apparatuses cannot be freely placed.
Thus, the body temperature of a physically challenged person, a newborn baby, or an infant is maintained by heating a room by an air conditioner all day. Heating apparatuses that utilize heat conduction by air have disadvantages that they are inefficient and that they cannot heat evenly. In addition, there are problems in that the volume of the heating apparatuses is large and that temperature is hard to be controlled. Further, optimum temperatures differ depending on individuals and it is hard to adjust the temperature so as to satisfy each individual by an air conditioner. Furthermore, since a room is periodically ventilated with air, the air conditioner consumes large amount of electric power. To continuously use the air conditioner is unfavorable in terms of energy saving.
Moreover, in the medical field, when operation with general anesthesia is performed, the body temperature of a patient decreases; therefore, the body temperature is necessary to be increased to prevent an infection when anesthesia wears off after the operation.
Further, after exposure to rain or snow in the mountains or getting out from the water while bathing in the sea, heat is drawn from skin by vaporization of water on the skin. The hand warmer cannot be used for warming wet skin. In addition, in the water, there are no other ways to heat a body except using a wet suit.
As a chip that utilizes wireless communication through radio waves, a wireless tag has been known. A wireless tag that is used for an individual identification technology is called an RFID tag. The RFID tag can be classified into two types based on whether a power source is built-in or supplied from the outside. The RFID tag can be classified into two types, an active RFID tag (active type) with a built-in power source, and a passive RFID tag (passive type) that is driven using electric power of radio waves from the outside, in which radio waves that include information related to an RFID can be transmitted. Of them, the active RFID tag incorporates a power source for driving the RFID tag and includes a battery as the power source. In addition, the passive RFID has a structure in which a power source for driving the RFID tag is generated using electric power of radio waves from the outside, whereby a structure without a battery is realized.
The present inventor discloses sports goods, playing goods, and training goods in which various functional circuits are formed of TFTs over flexible films in Patent Document 1 (Japanese Published Patent Application No. 2005-270640). Patent Document 1 discloses that a temperature sensor is provided to control the temperature by a CPU as well as a piezoelectric elements are provided for soles of running shoes as power generation elements so that feet are heated by heat generation in a TFT circuit by utilizing electric power the piezoelectric elements generate. Further, Patent Document 1 also discloses that a reception circuit is mounted on shoes. Furthermore, Patent Document 1 has a description in which a non-contact electric power transmission module which is capable of charging without contact is mounted on sports goods. Furthermore, Patent Document 1 also discloses that an auxiliary power source for making up for insufficient electric power (a primary battery or a secondary battery), such as a sheet battery is mounted or provided.
Moreover, in Patent Document 2 (Japanese Published Patent Application No. 2006-51343), a technique by which a wireless memory is provided over a flexible film, and the flexible sheet is attached to a head of a human or animal, or part of a human body, so that wireless communication with an external device is performed is disclosed.
Further, in Non-Patent Document 1 (H. Dembo et al. “RFCPUs on Glass and Plastic Substrates Fabricated by TFT Transfer Technology,” IEDM Tech. Dig. Papers, pp. 1067 to 1069, 2005), a technique of fabricating a CPU that operates with a radio signal of 13.56 MHz over a plastic substrate is disclosed.
Furthermore, an electronic thermometer in which temperature data showing a temperature is generated by detecting the temperatures of a battery for power source and a part to be measured, the temperature data is accumulated, and the accumulated temperature data is transmitted to the outside in response to a reading request signal from the outside is disclosed in Patent Document 3 (Japanese Published Patent Application No. S63-133027).
Furthermore, a sheet polyimide heater that can be bent and deformed in accordance with the shape of the surface of an object to be heated is disclosed in Patent Document 4 (Japanese Published Patent Application No. 2004-355882).
Furthermore, a technique in which a heat generating supporter to be attached to a body includes fibrous bodies, an electrode, and a sheet heat generating element a resistor element of which includes a resin component is disclosed in Patent Document 5 (Japanese Published Patent Application No. 2006-342449).